The nucleus within a eukaryotic cell is a complex but well-organized dynamic architecture that accommodates gene expression, replication, recombination and repair, as well as RNA processing and ribosome subunit assembly, making it the central hub for the determination of cell fate. Since variations in nuclear structures provide important diagnostic and prognostic information for pathologists, nucleus imaging is of vital concernment in the field of bioimaging.
Fluorescent materials have been proven to be a powerful implement for biological applications, including biosensors and cellular imaging. Since small fluorophores suffer from low photobleaching thresholds that limit their effectiveness in long-term and multi-dimensional applications, semiconductor quantum-dots (QDs) have emerged as a category of bright and photostable alternatives. However, QDs tend to aggregate and lose their luminescence in acid environments, (pH<5) or isotonic conditions. Moreover, the intrinsically-toxic elements within QDs, such as cadmium and selenium, are liable to release and in turn render toxicity, especially in radiation-caused oxidation environment. Although surface modification of QDs with biomolecules or biocompatible polymers could mitigate these detrimental problems, this strategy is complicated, and time-consuming. More importantly, surface modification often has a negative impact on the luminescence and dimension of QDs. As such, new fluorescent nanomaterials with high photoluminescence (PL) quantum yield, good photostability and biocompatibility remain in urge demand for optical biological applications.